David Becker said the devastation of what had just happened hit him as he checked the photographs, and realised how many people were injured

Getty photographer Becker said he had just walking into the media tent to file images of country singer Jason Aldean from the Las Vegas concert when shots first started firing, with a security guard at first telling him it was fire crackers, or sound equipment.

But after the third round of noises, the crowd began to flee.

Writing in response to questions from TIME and facilitated by Getty, the photographer said he stood on a table and started taking photos, saying: “(I was) thinking to myself still, that this isn’t really happening, it’s just the speakers popping.

“It was so dark I couldn’t really see what was happening, there were a lot of people crying, speaking on cellphones and ducking for cover.”

He said he struggled to understand what was going on, with the gunfire stopping and starting as people tried to hide in the dark.

He said: “People were cowering, they were very fearful for their lives. This was at a time before I had looked at any of the photographs and I still didn’t know exactly what was happening.”